gistfile1.clj

(defn close-files [col]
  (println "closing files...")
  (map #(.close %) col))

(defn -main [& args]
  (let [files (ref (list))]
  (try
    ;; User can open files (in which case they will be added to the files list),
    ;; work on them, close them (in which case they should be removed from the
    ;; files list), etc.
    (finally
     ;; Ideally the program should not exit without prompting the user about
     ;; whether to save files and would probably end up closing them earlier,
     ;; but this should ensure that the files are closed eventually.
     (close-files @files)))))